Work head



May 5, 1936.' c. H. HOWLAND-SHIIEARMAN WORK HEAD Filed July 27, 1934 2 Sheets-Sheet 1 IN VE NTO R Charles H. Ho w/and-Sheurman ATTORNEY IHH M y 1936- c. H. HOWLAND-SHEARMAN ,0 ,847

WORK HEAD Filed July 27, 1934 2 Sheets-Sheet 2 INVENTOR Chqr/ea H. Haw/and Shear/11 an ATTORNEY Patented May 5, 1936 UNITED STATES PATENT OFFICE 11 Claims.

This invention relates to improvements in work heads for use on machine tools. While it is primarily intended for use with the machine which is the subject matter of the copending application Serial No. '737,160, filed July 27, 1934, it is not limited to use specifically therewith but may be applied to a variety of other tools such as punch presses, hydraulic presses, broaches and the like.

The principal object is to provide means to preserve the material from fracture and distortion while work is being done upon it, and for this reason the device is called a fracture proofer as distinguished from the ordinary holding and stripping means hitherto employed.

A further object is to provide means of the above nature on the machine tool to apply definitel determinate resiliently variable pressures to the material during the progress of the work.

A still further purpose is to provide means to adjust the applied pressure to different classes of work and to read the intensity of the pressure directly on a scale.

Another object is to provide a device of the above character associated with the tool holding work head or ram of a machine together with common guiding means for both ram and fracture proofer.

Other specific objects of the invention are set forth in the following description and appended claims in accordance with the attached accompanying drawings, in which:

Figure 1 shows the fracture proofer and ram as applied to a machine tool and viewed from the operators position;

Figure 2 is a side view of the same, partially in section;

Figure 3 is an enlarged detail view of the indicating dial;

Figure 4 is a top view of the spring bolster;

Figure 5 is a side elevation of the same;

Figure 6 is a plan View of the lower ram member;

Figure 7 is a side elevation of the same;

Figure 8 is a detail view of the tool holder;

Figure 9 is an enlarged end view of the tool holder key;

Figure 10 is a side view of the same;

Figure 11 shows the method of securing the adjusting bevel gear;

Figure 12 is a side view of the adjusting shank;

Figure 13 is a bottom View of the same;

Figure 14 is a plan view of the adjusting nut;

Figure 15 is a vertical section of the same;

Figure 16 is a cross section of the thrust roller bearing;

Figure 17 is a top view of the spring guiding collar;

Figure 18 is a side elevation of the same;

Figure 19 shows the bridging key in perspective;

Figure 20 is a top view of the fracture proofer shell; and v Figure 21 is a side view of the same.

Referring to Figures 1 and 2, the numerals 22 and 23 indicate side plates forming part of the supporting frame of a machine tool, to which a ram guide 24 is secured by means of bolts 25. Slidable vertically in the guide 24 is a ram 26 comprising a body 21 and a lower member 28 secured to body 21 by bolts 28a.

A heavy cross pin 29 secured in the top of ram body 2! articulates the latter to a work arm or beam 30 which forms part of the machine tool and is movable vertically by power in any suitable manner.

The ram body 21 and lower member 28 contain a cylindrical bore 3| having an upper threaded portion 32 receiving an exteriorly threaded nut 33. The nut 33 has a central squared hole in which is slidably fitted a squared adjusting shank 34 having a cylindrical upper extension 35.

A hub 36, carrying a bevel gear 31, is secured to the cylindrical extension 35 by means of a pin 38. A retaining collar 39, disposed between the hub 36 and a flange 40 formed on the shank 34, is secured in the ram body 21 by means of screws 4|.

A bevel pinion 42 on the inner end of a shaft 43 journalled in the body 21, meshes with the bevel gear 31. The shaft 43 is provided with a hand wheel 44, and also carries a worm 45 adapted to drive a worm gear 45a on a cross shaft 46. A second worm 41, on the shaft 46, drives a second worm gear 48 rotatably mounted on a pin 49 fastened to the ram body 21. An indicating dial 50 is adjustably fastened to the second worm gear 41 so as to be rotatable therewith. A casing 5|, fastened to body 21, has an indicating mark 52 adapted to register with the graduations 53 of dial 50.

A spring guiding collar 54, rotatable about the square shank 34 and provided with longitudinal slots 55, has an upper flange 56 rotatably fitting in an annular groove 51 in the nut 33, and retains in 33a thrust bearing 58 which may be of the anti-friction type, Figure 16. The purpose of the slots in collar 54 is to permit the flange 56 to be sprung into the groove 5'! previous to the insertion of shank 34.

A compression spring 59 in the bore 3| is supported by a bolster 60 slidable in the lower ram member 28. The upper end of spring 59 is adapted to engage the collar 54 when the nut 33 is adjusted downward as hereinafter explained. A tool holder 6| is concentrically fitted in the lower end of the lower ram member 28 and is secured therein by a tapered key 62 shown in detail in Figures 9 and 10. A tool 63 is threaded into the holder 6|, a cylindrical guide portion 64 insuring correct alinement therein.

A fracture proofer shell 65, having an upper flange 66, is vertically slidable in guiding relation on the outer surface of lower ram member 28. 'A heavy bridge key 61, fitted through the bolster 60, bears on upward steps 68 formed on or secured to the shell 65 as shown in Figure 21, i

' sleeves 10 and are urged upward by coil springs 15; The ram body 21 has recesses 16 whose sides slidably engage the nuts 13 to prevent the latter from turning. V

- A collet 11 secured in the bottom of the shell 65 is slidable vertically on the tool holder 6|. A contact shoe lll preferably of a metal or other material having a high coefficient of friction, is secured in the bottom of collet l1 and is slidable on the tool 63.

The numeral 19 indicates a piece of material to be worked, which is supported by the machine table 80 having an insert or work plate 8| in which is an opening 82 corresponding to the bottom contour of the tool 63.

The operation of the device'is as follows:

The hand wheel 44 is first revolved, turning the shaft 43, pinion 42, gear 31 and shank 34, thereby screwing the nut 33 downward in the thread 32 until the collar 54 engages the spring 59. The dial 50 is now adjusted on the second worm gear 48 until its zero graduation registers with the indicating mark 52 on casing 5|.

ward and thereby compressing the spring 59. As the wheel 44 turns the shaft 43, the worm 45, worm gear 45a, cross shaft 46, second worm 41 and second worm gear 48 are actuated, revolving the dial 50. The dial 50 having been previously calibrated with the spring 59 so that graduations on the former represent corresponding compressive spring pressures, the pressure applied to the spring may be read directly by the operator as he turns the hand wheel. By this means any predetermined initial pressure within the limits of the spring may be applied downward through the bolster 60 and bridge key 61 to the fracture proofer shell 65, the resistance to downward movement of 'the latter being provided by the nuts 13.

'The contact shoe 18 normally projects'slightly beyond the tool 63, so that as the tool'and work material 19 approach engagement, either by downward movement of the ram 26 or by an initial upward'movement of the table 80, the shoe 18 first applies to the material the full predetermined initial pressure of the spring 59. The shoe [8, being accurately fitted around the tool 63, thus maps a work area beneath the tool while holdin The wheel 44 is nowfurther revolved, forcing the nut 33 down-' the immediately surrounding material firmly in compression. This compression by proper choice and setting of the spring 59 for the given material, is made sufiicient to prevent initial fracture or distortion of the material as the tool enters the latter.

As the ram 26 moves downwardly on the working stroke, forcing the tool 63 through the material, the fracture proofer shell 65, bridge key 61 and bolster 60 being held stationary by the contact of shoe 18 on the material surrounding the work area, the lower ram member 28 slides downward in the shell 65 and on the bolster 60. The spring 59 is thus further compressed by the downward movement of the ram 26 resiliently increasing the pressure applied by the shoe 18 as the work progresses and thereby preventing fracture or distortion around the work area. The work having been completed, the ram returns upward, the shoe l8 maintaining its grip on the material until the tool is completely withdrawn. When either by the final movement of the ram or by a downward setting of the table 80 the nuts 13 are permitted to engage the upper surface 14 of member'28, further expansion of spring 59 isprevented, andthe shoe 18 is disengaged from the remaining material which may then be removed and replaced by the next piece to be worked.

For different classes and sizes of material different fracture proofing pressures are necessary.

The required different pressures may be secured over a considerable range by setting the spring 59. If, however, pressures are needed falling out side the capacity of the spring 59 the latter may be replaced by a lighter or heavier similar spring according to requirements, the dial 59 also being replaced with a dial calibrated to the new spring. To remove the spring 59, the table 80 is withdrawn or removed to allow downward clearance under the ram. The handwheel 44 is then revolved until'the nut 33'is withdrawn from the spring 59 as shown in the figures; The bolts 28a are-removed and the lower ram member 28 carrying the fracture proofer is removed from the bot tom of ram body 21. Spring 59 is removed fr'om bore 3|; the required spring inserted therein, and the lower member 28 again fastened to 21 by the bolts 28a.

The use of the anti-friction bearing 58 which conveys the thrust of spring 59 from the collar 54 to the nut 33, prevents frictional twisting of the spring during adjustment.

The spring 59 being situated in the middle of the ram 26 and all parts of the ram and fracture proofer being concentrically guided, the fracture proofing pressure is applied evenly around and parallel to the center line of the tool, insuring accurate alinement and proper relationship of' the parts at all times.

It will be noted that the operation of changing springs does not alter the setting and correct alinement of the fracture proofer shell norits vertical setting with respect to the tool, these settings having been initially made by adjusting the heads 12 of bolts H. After a regrinding of the tool the bolts H are also turned to readjust the fracture proofer to the proper position of shoe 18 flush with or beyond the tool 64.

While the device is illustrated in its preferred form, the invention is not limited to the precise structure. shown, as various modifications may be made without departing from the scope of the appended claims.

What is claimed is:

1. In a machine tool, in combination, a reciprocable ram, a Work tool secured therein and adapted to be applied to a material to be worked, means to guide said ram, means concentrically operable by said ram to apply a predetermined resiliently increasing pressure tosaid material surrounding said tool to prevent fracture or distortion of said material during the application of said tool, and calibrated means to predetermine said pressure, the relative position of the work contact face of said pressure applying means and said tool normally remaining fixed during changes in said pre-determination.

2. In a machine tool, in combination, a reciprocable ram, a tool secured therein and adapted to be applied to a material to be Worked by a work stroke of said ram, means to guide said ram, means concentrically guided by said ram and including a, spring concentrically contained in said ram to apply a predetermined resiliently increasing pressure. to said material immediately surrounding said tool during said work stroke whereby said surrounding material may be preserved intact, and calibrated means to predetermine said pressure.

3. In a machine tool, in combination, a reciprocable ram, a tool secured therein and adapted to be applied to a material to be worked by a work stroke of said ram, means to guide said ram, means operable by said ram and including a spring concentrically contained in said ram to apply a predetermined resiliently increasing pressure to said material immediately surrounding said tool during said work stroke whereby said surrounding material may be preserved intact, and means to adjust said spring whereby said pressure may be predetermined the relative position of the work contact face of said pressure applying means and said tool normally remaining fixed during changes in said Dre-determination.

4. In a machine tool, in combination, a reciprocable ram, a tool secured therein and adapted to be applied to a material to be worked by a work stroke of said ram, means to guide said ram, means concentrically guided by said ram and including a spring concentrically contained in said ram to apply a predetermined resiliently increasing pressure to said material immediately surrounding said tool during said work stroke whereby said surrounding material may be preserved intact, and exteriorly operable means to determinably change the effective pressure of said spring the relative positions of the work contact face of said pressure applying means and said tool normally remaining fixed during said change,

5. In a machine tool, in combination, a reciprocable ram, a tool secured therein and adapted to be applied to a material to be worked by a work stroke of said ram, means to guide said ram, means concentrically guided by said ram and including a spring concentrically contained in said ram to apply a resiliently increasing pressure to said material immediately surrounding said tool during said work stroke whereby said surrounding material may be preserved intact, and exteriorly operable means to adjust the pressure of said spring including a visual dial calibrated with said spring to indicate the pressure thereof.

6. In a machine tool, in combination, a reciprocable ram, a work tool secured therein and adapted to be applied to a material to be worked, means to guide said ram, means concentrically operable by said ram to apply a resiliently increasing pressure to said material surrounding said tool to prevent fracture or distortion of said material during said application, and manual means to determinably vary said pressure the relative positions of the work contact face of said pressure applying means and said tool normally remaining fixed during said variation.

'7. In a machine tool, in combination, a reciprocable ram, a work tool secured therein and adapted to be applied to a material to be worked, means to guide said ram, means concentrically operable by said ram to apply a resiliently increasing pressure to said material surrounding said tool to prevent fracture or distortion of said material during said application, and manual means to vary said pressure including a visual dial adapted to indicate the pressure of said means at the beginning of said application.

8. In combination, a ram, a fracture proofer concentrically operable by said ram and including a spring concentrically contained in said ram, means to determinably adjust the pressure of said spring, means to adjust the position of said fracture proofer, and means independent of said last named means to change said spring the relative positions of said fracture proofer and said tool normally remaining fixed during the adjustment of said spring pressure.

9. In a work head, in combination, a reciprocable ram, means to secure a tool therein, means to guide said ram, a concentric cylindrical bore in said ram, a bolster slidable in said bore, a nut adjustably threaded in said bore, a spring disposed between said nut and said bolster, manual means extending outwardly through said ram to revolve said nut, an indicating dial cooperative with said manual means, a fracture proofer shell concentrically slidable on said ram and having a contact shoe slidably fitted around said tool, a bridge key laterally disposed through said bolster and engaging said shell, and means to adjust the position of said shell.

10. In a work head, in combination, a reciprocable ram, means to secure a tool therein, means to guide said ram, a concentric cylindrical bore in said ram, a bolster slidable in said bore, a nut adjustably threaded in said bore, a spring disposed between said nut and said bolster, manual means extending outwardly through said ram to revolve said nut, an indicating dial cooperative with said manual means, a fracture proofer shell concentrically slidable on said ram and having a contact shoe slidably fitted around said tool, a bridge key laterally disposed through said bolster and engaging said shell, means to adjust the position of said shell, and means to change said spring independently of said last named adjusting means.

11. In a work head, in combination, a tool adapted to engage a piece of material to be worked, means to actuate said tool, means operable by said actuating means to apply an increasing resilient pressure parallel to the line of motion of said tool to a predetermined area of said material adjacent to said tool during the actuation thereof, means to determinably graduate said pressure, and means to guide said actuating means the relative positions of the work contact face of said pressure applying means and said tool normally remaining fixed during said graduation.

CHARLES H. HOWLAND-SHEARMAN. 

